<html>
    <head>
        <title>Test</title>
        <style>

plaintext.simple { padding:0; }
plaintext.simple > text { margin:0; padding:0; display:block; background:none; color:inherit;}

plaintext.dark { background:#000; color:#fff; }
plaintext.light { background:#fff; color:#000; }

        </style>
    </head>
    <body>
Light:
<plaintext.simple.light>
This is plaintext without line numbers and light
</plaintext>
Dark:
<plaintext.simple.dark>
This is plaintext without line numbers and dark
</plaintext>


    </body>
</html>